Wireless communication network handovers of wireless user equipment that execute low-latency applications

ABSTRACT

A wireless communication network serves a User Equipment (UE) that executes a low-latency application. A source Application Server (AS) exchanges low-latency data with the UE over a source wireless access node based on application context for the UE. The application context for the UE comprises a user identifier, a session identifier, and a session pointer. A target AS receives a handover notice and responsively retrieves the application context for the UE from the source AS. The target AS exchanges additional low-latency data with the UE over a target wireless access node based on the application context for the UE that comprises the user identifier, the session identifier, and the session pointer.

RELATED CASES

This United States patent application is a continuation of U.S. patentapplication Ser. No. 17/122,118 that was filed on Dec. 15, 2020 and isentitled “WIRELESS COMMUNICATION NETWORK HANDOVERS OF WIRELESS USEREQUIPMENT THAT EXECUTE LOW-LATENCY APPLICATIONS.” U.S. patentapplication Ser. No. 17/122,118 is hereby incorporated by reference intothis United States patent application.

TECHNICAL BACKGROUND

Wireless communication networks provide wireless data services towireless user devices. Exemplary wireless data services includemachine-control, internet-access, media-streaming, andsocial-networking. Exemplary wireless user devices comprise phones,computers, vehicles, robots, and sensors. The wireless communicationnetworks have wireless access nodes which exchange wireless signals withthe wireless user devices over radio frequency bands. The wirelesssignals use wireless network protocols like Fifth Generation New Radio(5GNR), Long Term Evolution (LTE), Institute of Electrical andElectronic Engineers (IEEE) 802.11 (WIFI), and Low-Power Wide AreaNetwork (LP-WAN). The wireless access nodes exchange network signalingand user data with network elements that are often clustered togetherinto wireless network cores. The wireless access nodes are connected tothe wireless network cores over backhaul data links.

The wireless access nodes are presently being distributed acrossdifferent physical platforms. A Radio Unit (RU) is typically attached toa tower and has antennas and radios. The RU is linked to a DistributedUnit (DU) that typically handles the lower layers of baseband signalprocessing. The DU is physically linked to a Centralized Unit (CU) thattypically handles the higher layers of baseband signal processing and islinked to a network core. In some wireless communication networks, theCU also hosts some network elements that were previously in the networkcore.

The wireless user devices execute user applications. Some of the userapplications requires low-latency data communications. For example, anaugmented-reality video-conferencing application may have to annotateand share live video among multiple wireless user devices. To serve thelow-latency user applications, network elements called applicationservers are used to handle user data and/or control the handling of theuser data for a specific user application. For example, an applicationserver may annotate and share live video among augmented reality users.The application server may control other network elements that handlethe live video among the augmented reality users.

As a wireless user device moves around and changes wireless accessnodes, the wireless user device typically remains coupled to itsoriginal application server. Unfortunately, the extension of the userconnection back to the same application server adds unwanted latency tothe application session. Wireless access nodes do not handover wirelessuser devices in a manner that efficiently and effectively preserves theperformance of their low-latency applications. Moreover, the wirelesscommunication networks do not optimize their CUs to enhance theperformance of the low-latency applications.

TECHNICAL OVERVIEW

A wireless communication network serves a User Equipment (UE) thatexecutes a low-latency application. A source Application Server (AS)exchanges low-latency data with the UE over a source wireless accessnode based on application context for the UE. The application contextfor the UE comprises a user identifier, a session identifier, and asession pointer. A target AS receives a handover notice and responsivelyretrieves the application context for the UE from the source AS. Thetarget AS exchanges additional low-latency data with the UE over atarget wireless access node based on the application context for the UEthat comprises the user identifier, the session identifier, and thesession pointer.

DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a wireless communication network to handover awireless User Equipment (UE) that executes a low-latency application.

FIG. 2 illustrates an exemplary operation of the wireless communicationnetwork to handover the wireless UE that executes the low-latencyapplication.

FIG. 3 illustrates an exemplary operation of the wireless communicationnetwork to handover the wireless UE that executes the low-latencyapplication.

FIG. 4 illustrates a Fifth Generation (5G) communication network tohandover a wireless UE that executes a low-latency application.

FIG. 5 illustrates a source Radio Unit (RU), Distributed Unit (DU), andCentral Unit (CU) to handover the wireless UE that executes thelow-latency application.

FIG. 6 illustrates a target RU, DU, and CU to handover the wireless UEthat executes the low-latency application.

FIG. 7 illustrates the target CU that accepts the handover of thewireless UE that executes the low-latency application.

FIG. 8 illustrates a wireless network core to facilitate the handoverthe wireless UE that executes the low-latency application.

FIG. 9 illustrates a wireless UE that is handed-over when executing thelow-latency application.

FIG. 10 illustrates an exemplary operation of the 5G communicationnetwork to handover the wireless UE that executes the low-latencyapplication.

DETAILED DESCRIPTION

FIG. 1 illustrates wireless communication network 100 to handoverwireless User Equipment (UE) 101 that executes a low-latencyapplication. Wireless communication network 100 delivers a low-latencywireless data service to UE 101 like video-conferencing,augmented-reality, vehicle navigation, remote keyboard, machine-control,and/or some other wireless networking product. Wireless communicationnetwork 100 comprises wireless UE 101, wireless access nodes 111-112,User Plane Functions (UPFs) 113-114, Application Servers (AS) 115-116,and wireless network core 120. Wireless access node 111, UPF 113, and AS115 comprise source network elements that initially serve UE 101 beforea handover. After the handover, wireless access node 112, UPF 114, andAS 116 comprise target network elements that subsequently serve UE 101after the handover. The number of UEs, access nodes, UPFs, AS, and coresthat are depicted on FIG. 1 has been restricted for clarity, andwireless communication network 100 may comprise many more UEs, accessnodes, UPFs, AS, and cores.

Various examples of network operation and configuration are describedherein. In some examples, UE 101 executes a low-latency application likeaugmented-reality, vehicle-navigation, remote keyboard, or some otheruser data service. AS 115 serves the low latency-application in UE 101based on UE application context for UE 101. The UE application contextcharacterizes the current user session with data like applicationversion, session ID, user ID, session pointers, and other applicationsession metadata. Initially, source AS 115 transfers application datafor the low-latency application to source UPF 113 based on the UEapplication context for UE 101. Source UPF 113 transfers the applicationdata for the low-latency application to source access node 111. Sourceaccess node 111 wirelessly transfers the application data for thelow-latency application to UE 101. Source access node 111 then initiatesa handover of UE 101 to target access node 112—possibly in response toUE mobility. After the UE 101 attaches to target access node 112, sourceAS 115 transfers application data for the low-latency application tosource UPF 113 based on UE application context for UE 101. Source UPF113 transfers the application data for the low-latency application tosource access node 111. Source access node 111 transfers the applicationdata for the low-latency application to target access node 112. Targetaccess node 112 wirelessly transfers the application data for thelow-latency application to UE 101.

Responsive to the initiation of the handover, target access node 112transfers a handover notice to wireless network core 120. Wirelessnetwork core 120 transfers the handover notice to target UPF 114. TargetUPF 114 transfers the handover notice to target AS 116. Target AS 116retrieves the UE application context for UE 101 from source AS 115 basedon the handover notice. After the UE context retrieval, target AS 116transfers application data to target UPF 114 for the low-latencyapplication based on the retrieved UE application context for UE 101.Target UPF 114 transfers the application data for the low-latencyapplication to target access node 112. Target access node 112 wirelesslytransfers the application data for the low-latency application to UE101. Advantageously, wireless network core 120 efficiently andeffectively performs a handover of UE 101 in a manner that efficientlyand effectively preserves the performance of the low-latencyapplication.

In some examples, target AS 116 uses a Network Repository Function (NRF)to identify source AS 115 based on the ID for source UPF 113 and the IDfor the low-latency application. The NRF may be resident in wirelessnetwork core 120, and portions of the NRF may be distributed nearwireless access nodes 111-112. Source UPF 113 and AS 115 register withthe NRF and indicate their AS/UPF pairing to serve the low-latencyapplication. Source access node 111 signals wireless network core 120 toindicate the handover of UE 101 to target access node 112 and indicatessource UPF 113. Wireless network core 120 selects target UPF 114 and AS116 to serve UE 101 over target access node 112. Wireless network core120 signals target UPF 114 to connect UE 101 to AS 116 for thelow-latency application. Wireless network core 120 also signals targetUPF 114 to indicate source UPF 113. Target UPF 114 signals AS 116 toserve the low-latency application to UE 101 and to indicate source UPF113. Target AS 116 queries the NRF with the ID for UPF 113 and the IDfor the low-latency application. The NRF returns the ID for source AS115. Target AS 116 then uses the ID for source AS 115 to retrieve the UEcontext for UE 101 from source AS 115.

Wireless UE 101 and wireless access nodes 111-112 wirelessly communicateover wireless links 131-132 using Radio Access Technologies (RATs) likeFifth Generation New Radio (5GNR), Long Term Evolution (LTE), Instituteof Electrical and Electronic Engineers (IEEE) 802.11 (WIFI), Low-PowerWide Area Network (LP-WAN), and/or some other wireless protocol. TheRATs use electromagnetic frequencies in the low-band, mid-band,high-band, or some other portion of the electromagnetic spectrum.Wireless access nodes 111-112 communicate with each other over X2 link133. AS 115-116 communicate with each other over AS link 134. Wirelessaccess nodes 111-112 communicate with wireless network core 120 overbackhaul links 135-136. Wireless network core 120 communicates withexternal systems over external links 137. Links 133-137 use metalliccables, glass fibers, radio waves, or some other communication media.Links 133-137 use IEEE 802.3 (Ethernet), Time Division Multiplex (TDM),Data Over Cable System Interface Specification (DOCSIS), InternetProtocol (IP), 5GNR, LTE, WIFI, virtual switching, inter-processorcommunication, bus interfaces, and/or some other data communicationprotocols.

Although UE 101 is depicted as a smartphone, UE 101 might insteadcomprise a computer, robot, vehicle, or some other data appliance withwireless communication circuitry. Wireless access nodes 111-112 aredepicted as towers, but access nodes 111-112 may use other mountingstructures or no mounting structure at all. Wireless access nodes111-112 may comprise 5GNR gNodeBs, LTE eNodeBs, WIFI hot-spots, LP-WANbase stations, wireless relays, and/or some other form of wirelessnetwork transceivers. Wireless UE 101 and wireless access nodes 111-112comprise antennas, amplifiers, filters, modulation, and analog/digitalinterfaces. UE 101, access nodes 111-112, UPF 113-114, AS 115-116, andwireless network core 120 comprise microprocessors, software, memories,transceivers, bus circuitry, and the like. The microprocessors compriseDigital Signal Processors (DSP), Central Processing Units (CPU),Graphical Processing Units (GPU), Application-Specific IntegratedCircuits (ASIC), and/or the like. The memories comprise Random AccessMemory (RAM), flash circuitry, disk drives, and/or the like. Thememories store software like operating systems, user applications, radioapplications, and network functions. The microprocessors retrieve thesoftware from the memories and execute the software to drive theoperation of wireless communication network 100 as described herein.Wireless network core 120 comprises network elements like NRF, Accessand Mobility Management Function (AMF), Authentication and SecurityFunction (AUSF), Unified Data Management (UDM), Network Slice SelectionFunction (NSSF), Policy Control Function (PCF), Session ManagementFunction (SMF), User Plane Function (UPF), Application Function (AF)and/or some other network apparatus. In some examples, the networkelements in wireless network core 120 comprise Virtual Network Functions(VNFs) in one or more Network Function Virtualization Infrastructures(NFVIs).

FIG. 2 illustrates an exemplary operation of wireless communicationnetwork 100 to handover wireless UE 101 that executes the low-latencyapplication. The operation may differ in other examples. Source AS 115transfers initial data for the low-latency application to source UPF 113based on UE application context for UE 101 (201). For example, AS 115may annotate live video and use UPF 113 to distribute the annotatedvideo to multiple users. Source UPF 113 transfers initial data for thelow-latency application to source access node 111 (202). Source accessnode 111 wirelessly transfers the initial data for the low-latencyapplication to UE 101 (203). Source access node 111 initiates a handoverof UE 101 to target access node 112 (203).

Source AS 115 transfers intermediate data for the low-latencyapplication to source UPF 113 based on the UE application context for UE101 (204). Source UPF 113 transfers the intermediate data for thelow-latency application to source access node 111 (205). Source accessnode 111 transfers the intermediate data for the low-latency applicationto target access node 112 responsive to the handover initiation (206).Target access node 112 wirelessly transfers the intermediate data forthe low-latency application to UE 101 (207).

Responsive to the initiation of the handover, target access node 112transfers a handover notice to wireless network core 120 (207). Wirelessnetwork core 120 transfers the handover notice to target UPF 114 (208).Target UPF 114 transfers the handover notice to target AS 116 (209).Target AS 116 retrieves the UE application context for UE 101 fromsource AS 115 based on the handover notice (210). Target AS 116transfers additional data for the low-latency application to target UPF114 based on retrieved UE application context for UE 101 (210). TargetUPF 114 transfers the additional data for the low-latency application totarget access node 112 (211). Target access node 112 wirelesslytransfers the additional data for the low-latency application to UE 101(212). Target access node 112, UPF 114, and AS 116 are now the sourceaccess node, source UPF, and source AS for UE 101, and the operationrepeats during another handover to another target access node.

FIG. 3 illustrates an exemplary operation of wireless communicationnetwork 100 to handover wireless UE 101 that executes the low-latencyapplication. The operation may differ in other examples. Source AS 115applies UE context for UE 101 and exchanges initial data for thelow-latency application in UE 101 with source UPF 113. For example, AS115 may generate navigation instructions and transfer a geographic mapwith the navigation instructions to the user. Source UPF 113 and sourceaccess node 111 exchange the initial data for the low-latencyapplication. Source access node 111 and UE 101 wirelessly exchange theinitial data for the low-latency application. Source access nodes111-112 exchange handover signaling to handover UE 101.

After the initiation of the handover, source AS 115 continues to applythe UE context for UE 101 and transfers intermediate data for thelow-latency application in UE 101 to source UPF 113. Source UPF 113transfers the intermediate data for the low-latency application tosource access node 111. Source access node 111 transfers theintermediate data for the low-latency application to target access node112 responsive to the handover initiation. Target access node 112wirelessly transfers the intermediate data for the low-latencyapplication to UE 101.

Responsive to the handover initiation, target access node 112 transfersa handover notice to wireless network core 120. Wireless network core120 transfers the handover notice to target UPF 114. Target UPF 114transfers the handover notice to target AS 116. Target AS 116 retrievesthe UE application context for UE 101 from source AS 115 based on thehandover notice. Target AS 116 applies the retrieved UE context for UE101 to additional data for the low-latency application. Target AS 116and target UPF 114 exchange the additional data for the low-latencyapplication in UE 101. Target UPF 114 and target access node 112exchange the additional data for the low-latency application in UE 101.Target access node 112 and UE 101 wirelessly exchange the additionaldata for the low-latency application.

FIG. 4 illustrates a Fifth Generation (5G) communication network 400 tohandover wireless UE 401 that executes a low-latency application. 5Gcommunication network 400 comprises an example of wireless communicationnetwork 100, although network 100 may differ. 5G communication network400 delivers a low-latency wireless data service to UE 401 likevideo-conferencing, augmented-reality, vehicle navigation, remotekeyboard, machine-control, and/or some other wireless networkingproduct. 5G communication network 400 comprises UE 401, Radio Units(RUs) 411-412, Distributed Units (DUs) 413-414, Centralized Units (CUs)415-416, and wireless network core 420. Wireless network core 420comprises Access and Mobility Management Function (AMF) 421, SessionManagement Function (SMF) 422, and Network Repository Function (NRF)423. Wireless network core 420 typically includes other networkfunctions like Application Function (AF), User Plane Function (UPF),Authentication and Security Function (AUSF), Unified Data Management(UDM), Network Slice Selection Function (NSSF), and Policy ControlFunction (PCF). Source CU 415 comprises source UPF 431 and ApplicationServer Function (ASF) 433. Target CU 416 comprises target UPF 432 andASF 434. A source wireless access node comprises RU 411, DU 413, andportions of CU 415. A target wireless access node comprises RU 412, DU414, and portions of CU 416.

Source UPF 431 registers its Identity (ID) with core NRF 423 andindicates its ability to communicate with source ASF 433. Source ASF 433registers its ID with core NRF 423 and indicates its ability to servethe low-latency application. Target UPF 432 registers its ID with coreNRF 423 and indicates its ability to communicate with target ASF 434.Target ASF 434 registers its ID with core NRF 423 and indicates itsability to serve the low-latency application.

UE 401 and source CU 415 wirelessly exchange attachment signaling oversource RU 411 and DU 413. Source CU 415 and AMF 421 exchange attachmentsignaling for UE 401. AMF 421 and UE 401 exchange authenticationsignaling over source RU 411, DU 413, and CU 415. AMF 421 selects SMF422 to serve UE 401. AMF 421 and core SMF 422 exchange session signalingthat directs SMF 422 to serve UE 401 with low-latency communications.SMF 422 uses NRF to select source UPF 431 and source ASF 433 to serve UE401 with low-latency communications. SMF 422 and source UPF 431 exchangeN4 signaling that directs UPF 431 to serve UE 401 with low-latencycommunications to source ASF 433. AMF 421 and source CU 415 exchange N2signaling that directs CU 415 to serve UE 401 with the low-latencycommunications.

UE 401 and source RU 411 wirelessly exchange low-latency data for thelow-latency application. Source RU 411 and source DU 413 exchange thelow-latency data. Source DU 413 and source CU 415 exchange thelow-latency data responsive to signaling from AMF 421. Source CU 415 andsource UPF 431 exchange the low-latency data responsive to signalingfrom AMF 421 and SMF 422. Source UPF 431 and ASF 433 exchange thelow-latency data responsive to the signaling from SMF 422. ASF 433processes the low-latency data based on UE application context for UE401. The UE application context comprises low-latency application datalike user ID, session type, session ID, session pointers, and/or otherapplication session metadata.

Due to UE mobility or some other factor, source RU 411, DU 413, and CU415 initiate a handover of UE 401 to target RU 412, DU 414, and CU 416.CUs 415-416 exchange X2 handover signaling. During the handover, sourceASF 433 continues to process low-latency data per the UE applicationcontext and to transfer the low-latency data to source UPF 431. SourceUPF 431 continues to transfer the low-latency data to source CU 415.Source CU 415 now transfers the low-latency data and to target CU 416responsive to the X2 handover signaling. Target CU 416 transfers thelow-latency data to target DU 414 responsive to the X2 handoversignaling. Target DU 414 transfers the low-latency data to target RU412. Target RU 412 wirelessly transfers the low-latency data to UE 401.

In response to the X2 handover signaling and to transferring thelow-latency data for UE 401, target CU 416 transfers an N2 path switchrequest for UE 401 to core AMF 421. In response, AMF 421 transfers pathswitch instructions to core SMF 422 to switch UE 401 from source CU 415and UPF 431 to target CU 416 and UPF 432. SMF 422 transfers N4 signalingto target UPF 432 that directs UPF 432 to exchange low-latencycommunications for UE 401 between target CU 416 and target ASF 434 toserve the low-latency application. In response to the path switch forthe low-latency application, SMF 422 identifies source UPF 431 and thelow-latency application to target UPF 432 over N4 signaling. AMF 421 andtarget CU 416 exchange N2 signaling that directs CU 416 to serve UE 401with the low-latency communications to target UPF 432.

In response to the N4 signaling from SMF 422 that identifies thelow-latency application and source UPF 431 for UE 401, target UPF 432indicates source UPF 431 and the low-latency application for UE 401 totarget ASF 434. In response to the low-latency application handover,target ASF 434 transfers the IDs for source UPF 431 and the low-latencyapplication to core NRF 423. Core NRF 423 translates the IDs for sourceUPF 431 and the low-latency application into an ID for source ASF 433.Core NRF 423 indicates the ID for source ASF 433 to target ASF 434.Target ASF 434 uses the ID for ASF 433 to retrieve the UE applicationcontext for UE 401 for the current session from source ASF 433.

UE 401 and target RU 412 now wirelessly exchange low-latency data forthe low-latency application. Target RU 412 and target DU 414 exchangethe low-latency data. Target DU 414 and target CU 416 exchange thelow-latency data responsive to the N2 signaling from AMF 422. Target CU416 and target UPF 432 exchange the low-latency data responsive to theN2 signaling from AMF 421 and the N4 signaling from SMF 422. Target UPF432 and ASF 434 exchange the low-latency data to serve the low-latencyapplication in UE 401 based on the retrieved UE application context forUE 401.

FIG. 5 illustrates source Radio Unit (RU) 411, Distributed Unit (DU)413, and Central Unit (CU) 415 to handover wireless UE 401 that executesthe low-latency application. RU 411, DU 414, and CU 416 comprises anexample of wireless access node 111, although node 111 may differ.Source RU 411 comprises antennas, amplifiers, filters, modulation,analog-to-digital interfaces, DSP, memory, and transceivers (XCVRs) thatare coupled over bus circuitry. Source DU 413 comprises memory, CPU, andtransceivers that are coupled over bus circuitry. The memory in DU 413stores an operating system and 5GNR network applications like PhysicalLayer (PHY), Media Access Control (MAC), and Radio Link Control (RLC).Source CU 415 comprises memory, CPU, and transceivers that are coupledover bus circuitry. The memory in CU 415 stores an operating system andnetwork functions like UPF 432, ASF 434, Packet Data ConvergenceProtocol Function (PDCPF) 511, Service Data Adaptation Protocol Function(SDAPF) 512, and Radio Resource Control Function (RRCF) 513.

In source DU 413, RLC functions comprise Automatic Repeat Request (ARQ),sequence numbering and resequencing, segmentation and re-segmentation.MAC functions comprise buffer status, power control, channel quality,Hybrid Automatic Repeat Request (HARM), user identification, randomaccess, user scheduling, and QoS. PHY functions comprise packetformation/deformation, guard-insertion/guard-deletion,parsing/de-parsing, control insertion/removal,interleaving/de-interleaving, Forward Error Correction (FEC)encoding/decoding, channel coding/decoding, channelestimation/equalization, and rate matching/de-matching,scrambling/descrambling, modulation mapping/de-mapping, layermapping/de-mapping, precoding, Resource Element (RE) mapping/de-mapping,Fast Fourier Transforms (FFTs)/Inverse FFTs (IFFTs), and DiscreteFourier Transforms (DFTs)/Inverse DFTs (IDFTs).

In source CU 415, UPF 431 performs packet routing & forwarding; packetinspection, QoS handling, and PDU termination. ASF 433 supports one ormore low-latency applications in UE 401 like augmented reality, machinecontrol, and the like. PDCPF 441 performs security ciphering, headercompression and decompression, sequence numbering and re-sequencing,de-duplication. SDAPF 442 performs QoS marking and flow control. RRCF443 performs authentication, security, handover control, statusreporting, Quality-of-Service (QoS), network broadcasts and pages, andnetwork selection.

UE 401 is wirelessly coupled to the antennas in source RU 411 over 5GNRlinks. Transceivers in RU 411 are coupled to transceivers in source DU413 over fronthaul links like enhanced Common Public Radio Interface(eCPRI). Transceivers in source DU 413 are coupled to transceivers insource CU 415 over mid-haul links. Transceivers in source CU 415 arecoupled to network core 420 over backhaul links. The CPUs in DU 413 andCU 415 execute their operating systems, PHY, MAC, RLC, PDCPF 511, SDAPF512, RRCF 513, UPF 431, and ASF 433 to exchange 5GNR signals with UE 401over RU 411 and to exchange 5GC/X2 signaling and data with core 420 andother CUs.

In RU 411, the antennas receive wireless 5GNR signals from UE 401 thattransport uplink 5GNR signaling and data—including low-latencyapplication data. The antennas transfer corresponding electrical uplinksignals through duplexers to the amplifiers. The amplifiers boost theelectrical uplink signals for filters which attenuate unwanted energy.Demodulators down-convert the filtered uplink signals from their carrierfrequency. The analog/digital interfaces convert the demodulated analoguplink signals into digital uplink signals for the DSPs. The DSPsrecover uplink 5GNR symbols from the uplink digital signals and transferthe uplink 5GNR symbols to DU 413. In DU 413, the CPU executes thenetwork applications (PHY, MAC, and RLC) to process the uplink 5GNRsymbols and recover the uplink 5GNR signaling and data. The RLC in DU413 transfers UL data units to the PDCPF 511 in CU 415. In CU 415, theCPU executes the network functions (PDCPF 511, SDAPF 512, and RRCF 513)to process the uplink data units and recover the uplink 5GNR signalingand data.

RRCF 513 processes the uplink 5GNR signaling, downlink 5GC N2 signaling,and X2 signaling to generate new downlink 5GNR signaling, new uplink 5GCN2 signaling, and new X2 signaling. RRCF 513 transfers the new uplink5GC N2 signaling to core 420 and the X2 signaling to other CUs. SDAPF512 transfers corresponding N3 data to UPF 431. UPF 431 transfers the N3data to ASF 433. ASF 433 processes the uplink data per UE low-latencyapplication context like the user ID, session ID, session pointers, andso on. For example, ASF 433 may annotate and distribute livevideo-conferencing data for a multi-user augmented reality application.UPF 431 transfers the downlink data to SDAPF 512—including low-latencyapplication data. SDAPF 512 receives X2 data from other CUs. The 5GNRnetwork functions (RRCF 513, SDAPF 512, PDCPF 511) process the newdownlink 5GC signaling and data to generate corresponding downlink dataunits. PDCPF 511 in CU 415 transfers the downlink data units to the RLCin DU 413. The 5GNR network applications (RLC, MAC, PHY) process thedownlink data units to generate corresponding 5GNR symbols. DU 413transfers the downlink 5GNR symbols to RU 411. In RU 411, the DSPprocesses the downlink 5GNR symbols to generate corresponding digitalsignals for the analog-to-digital interfaces. The analog-to-digitalinterfaces convert the digital signals into analog signals formodulation. Modulation up-converts the analog signals to their carrierfrequency. The amplifiers boost the modulated signals for the filterswhich attenuate unwanted out-of-band energy. The filters transfer thefiltered electrical signals through duplexers to the antennas. Thefiltered electrical signals drive the antennas to emit correspondingwireless signals to 5GNR UE 401 that transport the downlink 5GNRsignaling and data.

When executed in CU 415, source UPF 431 registers its ID with NRF 423 incore 420 and indicates its ability to communicate with source ASF 433.When executed in CU 415, source ASF 433 registers its ID with NRF 423 incore 420 and indicates its ability to serve the low-latency application.UE 401 and RRCF 513 in source CU 415 wirelessly exchange attachmentsignaling over source RU 411 and DU 413. RRCF 513 in source CU 415 andAMF 421 in core 420 exchange N2 attachment signaling for UE 401. AMF 421and UE 401 exchange authentication signaling over source RU 411, DU 413,and CU 415.

SMF 422 in core 420 and source UPF 431 exchange N4 signaling thatdirects UPF 431 to serve UE 401 with low-latency communications tosource ASF 433. AMF 421 in core 420 and RRCF 513 in source CU 415exchange N2 signaling that directs CU 415 to serve UE 401 with thelow-latency communications.

UE 401 and source RU 411 wirelessly exchange low-latency data for thelow-latency application. Source RU 411 and source DU 412 exchange thelow-latency data. Source DU 413 and source CU 415 exchange thelow-latency data responsive to the signaling from AMF 421 in core 420.SDAPF 512 in source CU 415 and source UPF 431 exchange the low-latencydata responsive to the signaling from AMF 421 and SMF 422. Source UPF431 and ASF 433 exchange the low-latency data responsive to thesignaling from SMF 422. ASF 433 processes the low-latency data based onUE application context for UE 401.

Due to UE mobility or some other factor, RRCF 513 in CU 415 initiates ahandover of UE 401 to target RU 412, DU 414, and CU 416. RRCF 513 in CU415 and CU 416 exchange X2 handover signaling. During the handover,source ASF 433 continues to process low-latency data per the UEapplication context and to transfer low-latency data to source UPF 431.Source UPF 431 continues to transfer the low-latency data to SDAPF 512in source CU 415. SDAPF 512 in CU 415 now transfers the low-latency dataand to target CU 416 responsive to the X2 handover signaling. Inresponse to the low-latency application handover, source ASF 433receives a request from target ASF 434 for the UE application contextfor UE 401 for the current low-latency application. Source ASF 433transfers the UE application context for UE 401 for the currentlow-latency application to target ASF 434.

FIG. 6 illustrates target RU 412, DU 414, and CU 416 to handoverwireless UE 401 that executes the low-latency application. RU 412, DU414, and CU 416 comprises an example of wireless access node 112,although node 112 may differ. Target RU 412 comprises antennas,amplifiers, filters, modulation, analog-to-digital interfaces, DSP,memory, and transceivers (XCVRs) that are coupled over bus circuitry.Target DU 414 comprises memory, CPU, and transceivers that are coupledover bus circuitry. The memory in target DU 414 stores an operatingsystem and 5GNR network applications like Physical Layer (PHY), MediaAccess Control (MAC), and Radio Link Control (RLC). Target CU 416comprises memory, CPU, and transceivers that are coupled over buscircuitry. The memory in target CU 414 stores an operating system andnetwork functions like UPF 432, ASF 434, Packet Data ConvergenceProtocol Function (PDCPF) 611, Service Data Adaptation Protocol Function(SDAPF) 612, and Radio Resource Control Function (RRCF) 613.

In target DU 414, RLC functions comprise ARQ, sequence numbering andresequencing, segmentation and re-segmentation. MAC functions comprisebuffer status, power control, channel quality, HARQ, useridentification, random access, user scheduling, and QoS. PHY functionscomprise packet formation/deformation, guard-insertion/guard-deletion,parsing/de-parsing, control insertion/removal,interleaving/de-interleaving, FEC encoding/decoding, channelcoding/decoding, channel estimation/equalization, and ratematching/de-matching, scrambling/descrambling, modulationmapping/de-mapping, layer mapping/de-mapping, precoding, REmapping/de-mapping, FFTs/IFFTs, and DFTs/IDFTs.

In target CU 416, UPF 432 performs packet routing & forwarding, packetinspection, QoS handling, and PDU termination. ASF 434 supports one ormore low-latency applications in UE 401 like augmented reality, machinecontrol, and the like. PDCPF 611 performs security ciphering, headercompression and decompression, sequence numbering and re-sequencing,de-duplication. SDAPF 612 performs QoS marking and flow control. RRCF613 performs authentication, security, handover control, statusreporting, QoS, network broadcasts and pages, and network selection.

UE 401 is wirelessly coupled to the antennas in RU 412 over 5GNR links.Transceivers in RU 412 are coupled to transceivers in DU 414 overfronthaul links like eCPRI. Transceivers in DU 414 are coupled totransceivers in CU 416 over mid-haul links. Transceivers in CU 416 arecoupled to network core 420 over backhaul links. The CPUs in DU 414 andCU 416 execute their operating systems, PHY, MAC, RLC, PDCPF 611, SDAPF612, RRCF 613, UPF 432, and ASF 434 to exchange 5GNR signals with UE 401over RU 412 and to exchange 5GC/X2 signaling and data with core 420 andother CUs.

In RU 412, the antennas receive wireless 5GNR signals from UE 401 thattransport uplink 5GNR signaling and data—including low-latencyapplication data. The antennas transfer corresponding electrical uplinksignals through duplexers to the amplifiers. The amplifiers boost theelectrical uplink signals for filters which attenuate unwanted energy.Demodulators down-convert the filtered uplink signals from their carrierfrequency. The analog/digital interfaces convert the demodulated analoguplink signals into digital uplink signals for the DSPs. The DSPsrecover uplink 5GNR symbols from the uplink digital signals and transferthe uplink 5GNR symbols to DU 414. In DU 414, the CPU executes thenetwork applications (PHY, MAC, and RLC) to process the uplink 5GNRsymbols and recover the uplink 5GNR signaling and data. The RLC in DU414 transfers UL data units to the PDCPF 611 in CU 416. In CU 416, theCPU executes the network function (PDCPF 611, SDAPF 612, and RRCF 613)to process the uplink data units and recover the uplink 5GNR signalingand data. RRCF 613 processes the uplink 5GNR signaling, downlink 5GC N2signaling, and X2 signaling to generate new downlink 5GNR signaling, newuplink 5GC N2 signaling, and new X2 signaling. RRCF 613 transfers thenew uplink 5GC N2 signaling to core 420 and the X2 signaling to otherCUs. SDAPF 612 transfers corresponding N3 data to UPF 432—including thelow-latency application data. UPF 432 transfers the low latency data toASF 434. ASF 434 processes the uplink data per UE low-latencyapplication context like the user ID, session ID, session pointers, andso on. For example, ASF 434 may annotate and distribute livevideo-conferencing data for a multi-user augmented reality application.

In target CU 416, RRCF 443 receives the 5GC N2 signaling from core 420and X2 signaling from the other CUs. UPF 432 receives low-latencyapplication data from ASF 434. UPF 432 transfers the downlinklow-latency data to SDAPF 442. SDAPF 442 also receives data from otherCUs. The 5GNR network functions (RRCF 613, SDAPF 612, PDCPF 611) processthe new downlink 5GC signaling and data to generate correspondingdownlink data units. PDCPF 611 in CU 416 transfers the downlink dataunits to the RLC in DU 414. The 5GNR network applications (RLC, MAC,PHY) process the downlink data units to generate corresponding 5GNRsymbols. DU 414 transfers the downlink 5GNR symbols to RU 412. In RU412, the DSP processes the downlink 5GNR symbols to generatecorresponding digital signals for the analog-to-digital interfaces. Theanalog-to-digital interfaces convert the digital signals into analogsignals for modulation. Modulation up-converts the analog signals totheir carrier frequency. The amplifiers boost the modulated signals forthe filters which attenuate unwanted out-of-band energy. The filterstransfer the filtered electrical signals through duplexers to theantennas. The filtered electrical signals drive the antennas to emitcorresponding wireless signals to 5GNR UE 401 that transport thedownlink 5GNR signaling and data—including low-latency application data.

Target UPF 432 registers its ID with NRF 423 in core 420 and indicatesits ability to communicate with target ASF 434. Target ASF 434 registerswith NRF 423 in core 420 and indicates its ability to serve thelow-latency application.

Due to UE mobility or some other factor, target RRCF 613 receives X2handover signaling for UE 401 from CU 415. UE 401 attaches to RRCF 613over RU 412 and DU 414. SDAPF 612 in target CU 416 receives low-latencydata from CU 415 and transfers the low-latency data to PDCPF 612 whichtransfers the low-latency data to the RRC in DU 414. The PHY in DU 414transfers the low-latency data to target RU 412. Target RU 412wirelessly transfers the low-latency data to UE 401.

In response to the X2 handover signaling and in response to transferringthe low-latency data for UE 401 over SDAPF 612, RRCF 613 transfers an N2path switch request for UE 401 to AMF 421 in core 420. AMF 421 in core420 and RRCF 613 then exchange N2 signaling that directs SDAPF 612 toserve UE 401 with the low-latency communications to target UPF 432. Inresponse to the N4 signaling from SMF 422 in core 420 that identifiesthe low-latency application and source UPF 431 for UE 401, target UPF432 indicates source UPF 431 and the low-latency application for UE 401to target ASF 434. In response to the low-latency application handover,target ASF 434 transfers the IDs for source UPF 431 and the low-latencyapplication to NRF 423 in core 420. NRF 423 in core 420 returns the IDfor source ASF 433 to target ASF 434. Target ASF 434 uses the ID for ASF433 to retrieve the UE application context for UE 401 for the currentsession from source ASF 433.

UE 401 and target RU 412 now wirelessly exchange low-latency data forthe low-latency application. Target RU 412 and target DU 414 exchangethe low-latency data. The RLC in target DU 414 and the PDCPF 611 intarget CU 416 exchange the low-latency data responsive to the N2signaling from AMF 421 in core 420. SDAPF 612 and target UPF 432exchange the low-latency data responsive to the N2 signaling from AMF421 and the N4 signaling from SMF 422 in core 420. Target UPF 432 andASF 434 exchange the low-latency data responsive to the N4 signalingfrom SMF 422 in core 420. ASF 434 serves the low-latency application inUE 401 based on the retrieved UE application context for UE 401.

FIG. 7 illustrates target CU 416 to handover wireless UE 401 thatexecutes the low-latency application. CU 416 comprises an example of CUs115-116 and 415, although CUs 115-116 and 415 may differ. CU 416comprises hardware 701, hardware drivers 702, operating systems 703,virtual layer 704, and Virtual Network Functions (VNFs) 705. Hardware701 comprises Network Interface Cards (NIC), CPU, RAM, flash/diskdrives, and data switches (SW). Hardware drivers 702 comprise softwarethat is resident in the NIC, CPU, RAM, DRIVE, and SW. Operating systems703 comprise kernels, modules, applications, containers, hypervisors,and the like. Virtual layer 704 comprises virtual NICs (vNIC), virtualCPUs (vCPU), virtual RAM (vRAM), virtual Drives (vDRIVE), and virtualSwitches (vSW). VNFs 705 comprise the RRCF 613, SDAPF 612, PDCPF 613,UPF 432, and ASF 434. The NIC are coupled to target DU 414, source CU415, and network core 420. CU 416 may be located at a single site or bedistributed across multiple geographic locations. Hardware 701 executeshardware drivers 702, operating systems 703, virtual layer 704, and VNFs705 to serve UE 401 over DU 414. Target CU 416 exchanges 5GC signalingand data with network core 420 to serve UE 401 with the wireless dataservices.

FIG. 8 illustrates wireless network core 420 to handover wireless UE 401that executes the low-latency application. NFVI 420 comprises an exampleof wireless network core 120, although network core 120 may differ. NFVI420 comprises NFVI hardware 801, NFVI hardware drivers 802, NFVIoperating systems 803, NFVI virtual layer 804, and NFVI Virtual NetworkFunctions (VNFs) 805. NFVI hardware 801 comprises NIC, CPU, RAM,flash/disk drives, and SW. NFVI hardware drivers 802 comprise softwarethat is resident in the NIC, CPU, RAM, DRIVE, and SW. NFVI operatingsystems 803 comprise kernels, modules, applications, containers,hypervisors, and the like. NFVI virtual layer 804 comprises vNIC, vCPU,vRAM, vDRIVE, and vSW. NFVI VNFs 805 comprise Access and MobilityManagement Function (AMF) 421, Session Management Function (SMF) 422,and Network Repository Function (NRF) 423. Other VNFs likeAuthentication and Security Function (AUSF), User Plane Function (UPF),Unified Data Manager (UDM), Network Slice Selection Function (NSSF),Policy Control Function (PCF) are typically present but are omitted forclarity. NFVI 420 may be located at a single site or be distributedacross multiple geographic locations. The NIC are coupled to CUs 415-416and external systems. NFVI hardware 801 executes NFVI hardware drivers802, NFVI operating systems 803, NFVI virtual layer 804, and NFVI VNFs805 to serve UE 401 over CUs 415-416. NFVI 420 exchanges 5GC signalingand data with CUs 415-416 to serve UE 401 with the wireless dataservices.

AMF 421 performs N2/N1 termination, N1 ciphering & integrity protection,UE registration, SMF/PCF selection, UE connection/mobility management,UE authentication and authorization, UE security management, andtracking area updates. SMF 422 perform session establishment/management,network address allocation, N1 termination, downlink data notification,and traffic steering and routing. NRF 423 performs network functionauthentication and authorization, network function selection, andnetwork function security. Although not shown for clarity, AUSF performsUE authentication with Authentication and Key Agreement (AKA)credentials and handles UE authorizations. UDM handles UE context. UEsubscription data, and UE authentication keys. NSSF performs networkslice selection per UE, network slice authorization per UE, and AMFreselection per UE. PCF performs policy framework implementation, andpolicy control-plane distribution. UPF performs packet routing &forwarding, packet inspection, QoS handling, PDU interconnection, andmobility anchoring.

NRF 423 receives registrations from UPFs that indicate their IDs and ASFsupport. NRF 423 receives registrations from ASFs that indicate theirIDs and low-latency application support. AMF 421 receives attachmentsignaling for UE 401 from CU 415. AMF 421 and UE 401 exchangeauthentication signaling over source CU 415. AMF 421 selects SMF 422 toserve UE 401. AMF 421 and core SMF 422 exchange session signaling thatdirects SMF 422 to serve UE 401 with low-latency communications. SMF 422uses NRF 423 to select source UPF 431 and source ASF 433 to serve UE 401with low-latency communications. SMF 422 and source UPF 431 exchange N4signaling that directs UPF 431 to serve UE 401 with low-latencycommunications to source ASF 433. AMF 421 and source CU 415 exchange N2signaling that directs CU 415 to serve UE 401 with the low-latencycommunications.

AMF 421 receives an N2 path switch request for UE 401 from target CU416. In response, AMF 421 transfers path switch instructions to core SMF422 to switch UE 401 from source CU 415 and UPF 431 to target CU 416 andUPF 432. SMF 422 transfers N4 signaling to target UPF 434 that directsUPF 434 to exchange low-latency communications for UE 401 between targetCU 416 and target ASF 434 for the low-latency application. In responseto the path switch for the low-latency application, SMF 422 identifiessource UPF 421 and the low-latency application to target UPF 432 over N4signaling. AMF 421 and target CU 416 exchange N2 signaling that directsCU 416 to serve UE 401 with the low-latency communications to target UPF432. NRF 423 receives the IDs for source UPF 431 and the low-latencyapplication from CU 416. NRF 423 translates the IDs for source UPF 431and the low-latency application into an ID for source ASF 433. Core NRF423 indicates the ID for source ASF 433 to target CU 416.

FIG. 9 illustrates wireless UE 401 that is handed over when executingthe low-latency application. UE 401 comprises an example of UE 101,although UE 101 may differ. UE 401 comprises 5GNR radio 901 and usercircuitry 902. 5GNR radio 901 comprises antennas, amplifiers, filters,modulation, analog-to-digital interfaces, DSP, memory, and transceiversthat are coupled over bus circuitry. User circuitry 902 comprisesmemory, CPU, user interfaces, and transceivers that are coupled over buscircuitry. The memory in user circuitry 902 stores an operating system,low-latency applications (USER), and 5GNR network applications for PHY,MAC, RLC, PDCP, SDAP, and RRC. The antennas in 5GNR radio 901 arewirelessly coupled to RUs 411-412 over 5GNR links. Transceivers in 5GNRradios 901 are coupled to a transceiver in user circuitry 902. Atransceiver in user circuitry 902 is typically coupled to the userinterfaces like displays, controllers, memory, and the like. The CPU inuser circuitry 902 executes the operating system, PHY, MAC, RLC, PDCP,SDAP, and RRC to exchange 5GNR signaling and data with 5GNR RUs 411-412over 5GNR radio 901.

FIG. 10 illustrates an exemplary operation of 5G communication network400 to handover wireless UE 401 that executes the low-latencyapplication. The illustrated operation is exemplary and may vary inother examples. The RRC in UE 401 attaches to RRCF 511 in CU 415. RRCF511 selects AMF 421 for UE 401 based on UE location and possibly sliceID. RRCF 511 transfers initial UE signaling for UE 401 to AMF 421. Toauthenticate UE 401, AMF 421 interacts with an AUSF which interacts witha UDM to challenge and verify the identity of UE 401 over RRCF 513 in CU415. AMF 421 interacts with a UDM to obtain subscription data for UE 401like a low-latency DNN. AMF 421 interacts with an NSSF to obtain slicedata for the DNNs for UE 401 like prioritized and authorized low-latencyslice IDs for the low-latency DNN. AMF 421 selects SMF 422 based on thelow-latency DNN and the UE location. SMF 422 interacts with NRF 423 toselect a PCF based on the low-latency DNN and slice ID. AMF 421interacts with the PCF to obtain policy data like low-latencyQuality-of-Service Flow Indicators (QFIs) for UE 401 and its low-latencyDNN and slice ID. SMF 422 interacts with NRF 423 to select UPF 431 andASF 433 based on the low-latency DNN and UE location. SMF 422 allocatesa network address for the low-latency DNN to UE 401.

AMF 421 directs RRCF 511 to serve UE 401 using the low-latency DNN,slice ID, QFI, network addresses, and the like. SMF 422 directs UPF 431to serve UE 401 over DU 413 for the low-latency DNN. RRCF 513 in CU 415signals the RRC in UE 401 to use the low-latency DNN, slice ID, QFI,network addresses, and the like. The low-latency user application andthe SDAP in UE 401 exchange low-latency user data. The SDAP in UE 401and RLC in RU 411 exchange the low-latency user data. The RLC in DU 413and SDAPF 513 in CU 415 exchange the low-latency user data. In CU 415,SDAPF 513 and UPF 431 exchange the low-latency user data based on theDNN, slice ID, QFI, network address, and the like. UPF 431 and ASF 431exchange the low-latency user data based on the DNN, slice ID, QFI,network address, and the like. ASF 431 applies UE context for UE 401like application version, session ID, UE ID, session pointers, and otherlow-latency application metadata.

Due to UE mobility or some other factor, source RRCF 513 initiates ahandover of UE 401 to CU 416. RRCF 513 and RRCF 613 exchange X2 handoversignaling. During the handover, source ASF 433 continues to processlow-latency data per the UE application context and to transferlow-latency data to source UPF 431. Source UPF 431 continues to transferthe low-latency data to source SDAPF 513. Source SDAPF 513 now transfersthe low-latency data and to target SDAPF 612 responsive to the X2handover signaling. SDAPF 612 transfers the low-latency data to targetDU 414 responsive to the X2 handover signaling. Target DU 414 transfersthe low-latency data to UE 401 over the RU.

In response to the X2 handover signaling and to transferring thelow-latency data for UE 401, RRCF 613 transfers an N2 path switchrequest for UE 401 to core AMF 421. In response, AMF 421 transfers pathswitch instructions to core SMF 422 to switch UE 401 from source CU 415to target CU 416. SMF 422 uses NRF 423 to select UPF 432 and ASF 434.SMF 422 transfers N4 signaling to target UPF 432 that directs UPF 432 toexchange low-latency communications for UE 401 between SDAPF 612 andtarget ASF 434 to serve the low-latency application. In response to thepath switch for the low-latency application, SMF 422 identifies sourceUPF 421 and the low-latency application to target UPF 432 over N4signaling. AMF 421 and target RRCF 612 exchange N2 signaling thatdirects CU 416 to serve UE 401 with the low-latency communications totarget UPF 432.

In response to the N4 signaling from SMF 422 that identifies thelow-latency application and source UPF 431 for UE 401, target UPF 432indicates source UPF 431 and the low-latency application for UE 401 totarget ASF 434. In response to the low-latency application handover,target ASF 434 transfers the ID for source UPF 431 and the ID for thelow-latency application to core NRF 423. Core NRF 423 translates the IDsfor source UPF 431 and the low-latency application into an ID for sourceASF 433. Core NRF 423 indicates the ID for source ASF 433 to target ASF434. Target ASF 434 uses the ID for ASF 433 to retrieve the UEapplication context for UE 401 for the current session from source ASF433—possibly over the X2 link.

UE 401 and target RU 412 now wirelessly exchange low-latency data forthe low-latency application. Target RU 412 and target DU 414 exchangethe low-latency data. Target DU 414 and SDAPF 612 in target CU 416exchange the low-latency data responsive to the N2 signaling from AMF422. SDAPF 612 and target UPF 432 exchange the low-latency dataresponsive to the N2 signaling from AMF 421 and the N4 signaling fromSMF 422. Target UPF 432 and ASF 434 exchange the low-latency dataresponsive to the N4 signaling from SMF 422, ASF 434 serves thelow-latency application in UE 401 based on the retrieved UE applicationcontext for UE 401.

The wireless data network circuitry described above comprises computerhardware and software that form special-purpose network circuitry tohandover wireless UEs that execute low-latency applications. Thecomputer hardware comprises processing circuitry like CPUs, DSPs, GPUs,transceivers, bus circuitry, and memory. To form these computer hardwarestructures, semiconductors like silicon or germanium are positively andnegatively doped to form transistors. The doping comprises ions likeboron or phosphorus that are embedded within the semiconductor material.The transistors and other electronic structures like capacitors andresistors are arranged and metallically connected within thesemiconductor to form devices like logic circuitry and storageregisters. The logic circuitry and storage registers are arranged toform larger structures like control units, logic units, andRandom-Access Memory (RAM). In turn, the control units, logic units, andRAM are metallically connected to form CPUs, DSPs, GPUs, transceivers,bus circuitry, and memory.

In the computer hardware, the control units drive data between the RAMand the logic units, and the logic units operate on the data. Thecontrol units also drive interactions with external memory like flashdrives, disk drives, and the like. The computer hardware executesmachine-level software to control and move data by driving machine-levelinputs like voltages and currents to the control units, logic units, andRAM. The machine-level software is typically compiled from higher-levelsoftware programs. The higher-level software programs comprise operatingsystems, utilities, user applications, and the like. Both thehigher-level software programs and their compiled machine-level softwareare stored in memory and retrieved for compilation and execution. Onpower-up, the computer hardware automatically executesphysically-embedded machine-level software that drives the compilationand execution of the other computer software components which thenassert control. Due to this automated execution, the presence of thehigher-level software in memory physically changes the structure of thecomputer hardware machines into special-purpose network circuitry tohandover wireless UEs that execute low-latency applications.

The above description and associated figures teach the best mode of theinvention. The following claims specify the scope of the invention. Notethat some aspects of the best mode may not fall within the scope of theinvention as specified by the claims. Those skilled in the art willappreciate that the features described above can be combined in variousways to form multiple variations of the invention. Thus, the inventionis not limited to the specific embodiments described above, but only bythe following claims and their equivalents.

What is claimed is:
 1. A method of operating a wireless communicationnetwork to serve User Equipment (UE) that executes a low-latencyapplication, the method comprising: a source Application Server (AS)exchanging low-latency data with the UE over a source wireless accessnode based on application context for the UE that comprises a useridentifier, a session identifier, and a session pointer; a target ASreceiving a handover notice and responsively retrieving the applicationcontext for the UE from the source AS; and the target AS exchangingadditional low-latency data with the UE over a target wireless accessnode based on the application context for the UE that comprises the useridentifier, the session identifier, and the session pointer.
 2. Themethod of claim 1 wherein the application context for the UE furthercomprises a low-latency application version.
 3. The method of claim 1wherein the application context for the UE further comprises alow-latency application metadata.
 4. The method of claim 1 wherein theapplication context for the UE comprises low-latency application sessionparameters for the UE.
 5. The method of claim 1 wherein the sourcewireless access node and the target wireless access node comprise FifthGeneration New Radio (5GNR) access nodes.
 6. The method of claim 1wherein the low-latency application comprises a video-conferencingapplication.
 7. The method of claim 1 wherein the low-latencyapplication comprises an augmented-reality application.
 8. The method ofclaim 1 wherein the low-latency application comprises avehicle-navigation application.
 9. The method of claim 1 wherein thelow-latency application comprises a remote-keyboard application.
 10. Themethod of claim 1 wherein the low-latency application comprises amachine-control application.
 11. A wireless communication network toserve User Equipment (UE) that executes a low-latency application, thewireless communication network comprising: a source Application Server(AS) configured to exchange low-latency data with the UE over a sourcewireless access node based on application context for the UE thatcomprises a user identifier, a session identifier, and a sessionpointer; a target AS configured to receive a handover notice andresponsively retrieve the application context for the UE from the sourceAS; and the target AS configured to exchange additional low-latency datawith the UE over a target wireless access node based on the applicationcontext for the UE that comprises the user identifier, the sessionidentifier, and the session pointer.
 12. The wireless communicationnetwork of claim 11 wherein the application context for the UE furthercomprises a low-latency application version.
 13. The wirelesscommunication network of claim 11 wherein the application context forthe UE further comprises a low-latency application metadata.
 14. Thewireless communication network of claim 11 wherein the applicationcontext for the UE comprises low-latency application session parametersfor the UE.
 15. The wireless communication network of claim 11 whereinthe source wireless access node and the target wireless access nodecomprise Fifth Generation New Radio (5GNR) access nodes.
 16. Thewireless communication network of claim 11 wherein the low-latencyapplication comprises a video-conferencing application.
 17. The wirelesscommunication network of claim 11 wherein the low-latency applicationcomprises an augmented-reality application.
 18. The wirelesscommunication network of claim 11 wherein the low-latency applicationcomprises a vehicle-navigation application.
 19. The wirelesscommunication network of claim 11 wherein the low-latency applicationcomprises a remote-keyboard application.
 20. The wireless communicationnetwork of claim 11 wherein the low-latency application comprises amachine-control application.